Motomu Sakai

Propylene/propane and ethylene/ethane separation was examined with Ag-exchanged X-type zeolite membrane (Ag-X membrane). The Na-X membrane was prepared on a porous tubular α-alumina support by a secondary growth method. The resulting Na-X membrane was ion-exchanged by using AgNO₃ aq. Olefin selectivities in both mixtures were markedly improved after the ion exchange from Na to Ag cation. The Ag-X membrane exhibited a maximum propylene selectivity of 55.4 with a permeance of 4.13 × 10<

• Pure inorganic zeolite membrane was used for FO for the first time. • ZSM-5 membrane showed high salt rejection performance by a molecular sieving effect. • ZSM-5 membrane showed stable performance in intermittent use for more than one month. A potential of zeolite membrane in forward osmosis operation was investigated for the first time. A hydrophilic zeolite, ZSM-5, membrane was prepared on an α-alumina tubular support by a secondary growth method. NaCl aqueous solution and distilled water w

We investigated the adsorption properties of propylene and propane on an olefin-selective Ag-X membrane and discussed the contribution of adsorption selectivity to propylene/propane separation performance through this membrane. The isotherms of propylene and propane on Ag-X membranes were measured in unary systems at 313 K. The amount of propylene adsorbed on the Ag-X membrane at a lower pressure increased remarkably compared with that on the Na-X membrane. Such a change of adsorption property c

Water treatment of heavy metals using zeolite membranes in forward osmosis was demonstrated. A continuous Na-ZSM-5, aluminosilicate zeolite, crystal layer was synthesized on the outer surface of a porous tubular α-alumina support and used as the forward osmosis membrane. The rejection performances and fouling resistances of Na-ZSM-5 membrane were studied. Na-ZSM-5 membrane exhibited a high rejection performance of 99 % for various metal species (As(III), As(V), Se(IV), Se(VI), Cr(VI)). This supe

Tubular zeolite *BEA membrane was prepared by a hydrothermal secondary growth method in the absence of an organic structure directing agent (OSDA). Membrane formation process was carefully observed by using FE-SEM, XRD, and N2 adsorption, and the role of seed crystals on the support surface was discussed. Seed crystals loaded on the outer surface of a tubular porous alumina support partially dissolved and a small amount of seeds remained in an amorphous layer formed on the support surface in the

A novel preparation method was proposed for a metal-organic framework (MOF) monolith using a simple one-pot synthesis method. A MOF tubular monolith was successfully prepared by the hydrothermal treatment for an α-Al₂O₃ monolith in an aqueous solution of 1,3,5-benzenetricarboxylic acid and nitric acid without the addition of a metal source. The effects of temperature and the HNO₃ concentration in the synthesis solution on the crystallization behavior of MIL-96 we

Silicalite-1 membrane was prepared on an outer surface of a tubular α-alumina support by a secondary growth method. Changes of defect amount and crystallinity during secondary growth were carefully observed. The defect-less well-crystallized silicalite-1 membrane was obtained after 7-days crystallization at 373 K. The silicalite-1 membrane became (h0l)-orientation with increasing membrane thickness, possibly because the orientation was attributable to “evolutionally selection”. The (h0l)-oriente

Reverse water gas shift (RWGS) is attracting attention as one of the promising technologies for CO₂ conversion. Selective removal of H₂O from the reaction system can improve the CO₂ conversion beyond the equilibrium conversion of RWGS in a conventional reactor. In this study, a conventional plug-flow reactor without membrane, and two types of RWGS membrane reactors using ZSM-5 membranes, were developed. The yield of CO without membrane (<i>Case 1</i>) was almost

The micropore volumes and effective pore sizes of two types of silicalite-1 membranes were compared with those of a typical silicalite-1 powder. The silicalite-1 membrane with fewer grain boundaries in the membrane layer showed similar micropore volume and effective pores size to those of the silicalite-1 powder. In contrast, when the silicalite-1 membrane contained many grain boundaries, relatively small micropore volume and effective pore size were observed, suggesting that narrowing and obstr

Ag⁺ was introduced into *BEA-type zeolite membrane by an ion-exchange method to enhance olefin selectivity. Ag-*BEA membrane exhibited superior olefin separation performance for both ethylene/ethane and propylene/propane mixtures. Particularly, the separation factor for ethylene at 373 K reached 57 with the ethylene permeance of 1.6×10^-7 mol m^-2 s^-1 Pa^-1 . Adsorption properties of olefin and paraffin were evaluated to discuss contribution of

AEI-type zeolite membrane for dehydration was prepared, and a flow-type membrane reactor for the esterification of acetic acid and ethanol by AEI membrane was developed. A synthesized AEI membrane had suitable molecular sieving property for gas separation (H₂/<i>i</i>-butane and CO₂/CH₄) and pervaporation (H₂O/acetic acid). AEI membrane showed H₂O permeance of 6.2 × 10^-7 mol m^-2 s^-1 Pa^-1 with a sep

This study investigated the permeation behaviors of <i>n</i>-hexane and 2-methylpentane through two-types of silicalite-1 membranes that have different pore-connectivity. The permeation mechanisms of these hydrocarbons were able to be explained by the adsorption-diffusion model. In addition, the fluxes through silicalite-1 membranes could be expressed by the modified Fick's first law. The hydrocarbon fluxes through S-1_S with better pore-connectivity were ca. 3-20 times larger than tho

Zeolites have been used as a separation membrane material by taking advantages of their unique adsorption properties and molecular sieving properties based on the micropores. Zeolite membranes are widely used in practical applications, mainly for dehydration of organic solvents. Furthermore, the research and development continue toward large-scale implementation in the energy and carbon neutral field. The high heat and chemical resistance of zeolite membranes are also expected to be utilized as

Alkaline treatment with surfactant was applied to silicalite-1 membrane for defect healing.